1. Honors Biology: Chapter 2
Chemistry of Life
Honors Biology: Chapter 2

2. Matter Everything in the universe is made up of matter.
Matter- anything occupying space and has mass.
Mass- amount of matter an object has.
Weight- force of gravity on a given mass.
Q: Would your weight or mass change if you went to the moon?

3. Elements and Atoms
Elements- pure substances that cannot be broken down chemically into simpler kinds of matter.
100+ elements have been discovered.
Less than 30 are important to living things.
Over 90% of the mass of living things consists of:
Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)

4. Elements and Atoms
Periodic Table of Elements- lists information about each element including the element’s
Chemical symbol- 1-3 letters
Atomic number
Atomic mass

5. Elements and Atoms
Atom- simplest particle of an element that retains all of the properties of that element.
Nucleus

6. Elements and Atoms 3 Subatomic Particles in Atoms
Proton- Positively charged particle found in the atom’s nucleus. ATOMS OF AN ELEMENT ALWAYS HAVE THE SAME NUMBER OF PROTONS.
Neutron- Found within the nucleus and has no charge.
Electron- Small negatively charged particles with very little mass.
Move in orbitals found outside of the nucleus.

7. Elements and Atoms Nucleus Atomic Number = # of protons
Most of the atom’s mass
Contains protons and neutrons
Atomic Number = # of protons
Mass Number = # of protons + # of neutrons
Q: How can you determine the number of neutrons an atom has?
A: Mass number – Atomic number = # of neutrons

8. Elements and Atoms Atoms have a net charge of ZERO.
# of Protons (+) = # of electrons (-)
Orbital- 3D region around the nucleus indicating the probable location of an electron.
Combination of all orbitals  electron cloud
Farther from nucleus  greater electron’s energy

9. Elements and Atoms Orbitals and energy levels:
Each energy level corresponds to certain orbitals that can hold a set number of electrons.
First energy level has 1 orbital- holds maximum of 2
Second energy level has 4 orbitals that hold 2 electrons each (total of 8).

10. Elements and Atoms
Isotopes- Atoms of the same element that have a different number of neutrons (number of protons DOES NOT change).
Changes atomic mass

11. Carbon Isotopes

12. Compounds
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14. Compounds
Atoms of most elements readily combine with the same/different atoms or elements to make compounds.
Compound- atoms of 2+ elements in fixed proportions.
Ex: Water (H2O)

15. Compounds
Chemical and physical properties differ between compounds and the elements making them up.
Number and arrangement of e- determines how elements combine and form compounds.
Atoms are stable/less reactive when highest energy level is full. Ex: Noble gases

16. Chemical Bonds Attractive forces holding atoms together. Covalent Bond
Ionic Bond
Hydrogen bond

17. Covalent Bond
Formed when 2 atoms SHARE 1+ pairs of valence electrons.

18. Ionic Bonds Transfer of e- from a metal atom to a nonmetal atom.
More stability for the atoms involved.
Creates ions (charged atoms that have gained/lost e-)

19. ??Element or Compound?? HCl CO2 Cl Li H2O HCl, CO2, and H2O- compounds
Cl and Li- elements

20. Energy

21. Energy and Matter Energy- the ability to do work.
Forms of energy include:
Radiant (light) energy
Thermal (heat) energy
Chemical energy
Electrical energy
Mechanical energy

22. States of Matter
All atoms and molecules in a substance are in constant motion.
Motion of and spacing between atoms/molecules determine the substances state:
Solid
Liquid
Gas

23. Solids Move less rapidly than liquids or gases Fixed volume
Molecules/atoms more closely linked than liquids or gases (with the exception of H2O).

24. Liquid
Maintain a fixed volume, but particles move more freely  ability to flow and conform to container’s shape.

25. Gas Particles move rapidly Little to no attraction to each other.
Fill the volume of the container they occupy.
Start 10/10

26. Energy and Chemical Reactions
Chemical Reaction- change from one substance to another.
Energy is absorbed/released when bonds are broken and new bonds are formed.
Ex: CO2 + H2O  H2CO3 (see pg 36 Fig 2-6)
Q: Where are the reactants? Products?
Q: What does the arrow represent?

27. Energy and Chemical Reactions
Reactants  Products
Products  Reactants
Number of each type of atom must be EQUAL on both sides of the equation.
Reversible reactions shown using arrows pointing in both directions.

28. Where Do You Get Your Energy??
Sugars, proteins, and fats in your food get broken down into CO2, H2O, and other products.
Breaking bonds  release of energy to be used in building & maintaining cells, tissues, and organs.

29. Starting Reactions
Activation energy- amount of energy needed to start a reaction.
Usually a large amount of energy is needed to start reactions.
Catalysts- reduce the activation energy needed for a reaction without being changed/destroyed.
Enzymes- “special” proteins
RNA molecules

30. Activation Energy

31. Oxidation-Reduction Reactions
Oxidation-reduction reaction = redox
Oxidation reaction: reactant loses 1+ electrons  more + charge
Reduction reaction: reactant gains 1+ electrons  more – charge
Oxidation reactions are always followed by a reduction reaction.
Over the years, exposed copper develops a thin layer of black copper oxide, and as time passes, traces of carbon dioxide in the air contribute to the formation of greenish copper carbonate. This explains why the Statue of Liberty, covered in sheets of copper, is green, rather than having the reddish-golden hue of new, uncorroded copper.

32. Redox Reactions
Forming Na+ Cl- involves oxidation and reduction reactions.
Na donates an e- to Cl  oxidation of Na to form Na+
Cl accepts an e-  reduction of Cl to form Cl-

33. Enzymes Type of protein.
Most enzyme reactions are reversible (arrow goes both ways).
Maintain homeostasis: reactions would not occur fast enough without them.
“–ase” = enzyme
ONLY react with specific substrates.

34. Enzymes

35. THE END!